Here are a few good tips & tricks for sewing a bias cut skirt:

1. Alternate how you lay out your pattern when cutting the fabric to prevent twisting.
2. Handle fabric cut on the bias gently to prevent warping.
3. Use ultra-tiny stitches at the end of your dart to lock it in.
4. Sew up the side seams with a narrow zigzag to account for gravitational stretch.
5. Stay Stitch the waist before attaching elastic to avoid bumps.
6. Hang the skirt for 24 hours before hemming because the bias always drops.